1. Field of the Invention
The present invention relates to apparatus and methods for transferring information between a local and system bus wherein the users and peripherals connected with these busses are each characterized by differing lengths of the units of digital information processed. In particular, the present invention relates to a method of apparatus for permitting the use of both 8 and 16 bit machines in the same system.
2. Description of the Prior Art
Semiconductor microprocessors have predominantly been designed to transfer data or digital information within a microprocessor computer system, for example as between a processor and a memory, wherein the information consisted of eight-bit bytes. Thus, a large number of peripheral devices are organized and accessed in byte quantities.
However, the sophistication, power and complexity of semiconductor microprocessors continues to increase at an accelerating rate wherein many microprocessor computer systems are now based upon manipulation of quantities having a word or 16 bit lengths. Thus, many prior art eight-bit memories can no longer be accessed by central processors which assume that each memory location contains a sixteen-bit word. Therefore, a substantial number of prior art microprocessor computer systems, including peripherals, have become incompatible with newer sixteen-bit microprocessor systems now being developed and marketed. What is needed then is some means by which a computer system may be organized so as to be compatible with circuit users and peripherals based both upon byte and word length quantities.